Originally Posted by cribble
ICT SLB
After a good deal of thought, I am still unable to grasp how rotation sensors(the ring laser gyros) can do an output for translation and thus velocity?
The Laser gyros are not true gyros. In fact they are, in fact, optical devices (glass block or coils of fiber optic cable) with a fixed path. The laser is shone along the main axis in both directions and, after going around the path, interferes with itself to give rise to fringes (areas of brighter & darker light) which is detected to give a measurement of movement in the direction of the light path. The light paths differ by the actual movement of the platform in the time it takes to go around the path. No movement, no fringes as there is now no difference in the effective light path. There are normally 3 laser gyros at mutual right angles to each other so that the actual resolved accelerations & angles can be calculated & read out.
This is a VERY simplified version of what's inside an IRU and doesn't even go into the calculations - my defence is that I only install & test inertial systems not build them and it's been longer than I care to think since I sat in the Singer-Kearfott lecture at Boring....